A structure for the rear part of a vehicle body includes a pair of left and right rear side frames extending in the front-rear direction of a vehicle, and a rear sub-frame supported by the rear side frames. As a similar technique, a suspension frame mounting structure includes a pair of left and right front side frames (front side members) extending in the front-rear direction of a vehicle, and a front sub-frame (suspension frame) mounted on the front side frames. In this technique, the front sub-frame has front and rear fastening sections to be fastened with the front side frames, and the positions of the rear fastening sections are aligned in a height direction with the center of the cross-section of the front side frames.
With such a suspension frame mounting structure, it is possible to input load to the center of the cross-section of the front side frames from the front sub-frames when the front sub-frames are moved (e.g., see Patent Literature 1).
A rear sub-frame (suspension sub-frame of the vehicle) used in the structure for the rear part of the vehicle body may include left and right longitudinal members extending in the front-rear direction of the vehicle body, a front lateral member extending in a vehicle width direction and stretched between the left and right longitudinal members, and a rear lateral member extending in the vehicle width direction in the vehicle rear part behind the front lateral member and stretched between the left and right longitudinal members (e.g., see Patent Literature 2).
Upper and lower support sections that support an upper link and a lower link, respectively, are provided on the front lateral member. An arm support sections that supports the lower arm is provided on the rear lateral member. As in the suspension frame mounting structure of Patent Literature 1, the pair of rear side frames extend in the front-rear direction of the vehicle, and the rear sub-frame includes front and rear fastening sections formed on the left and right longitudinal members of the rear sub-frame, with the front and rear fastening sections being mounted on the rear side frames. In the rear sub-frame mentioned above, at least one of the support sections of the upper and lower support sections is formed as a separate member other than the front lateral member.
Since at least one of the support sections of the upper and lower support sections is formed as a separate member other than the front lateral member in the rear sub-frame disclosed in Patent Literature 2, it is possible to improve measurement accuracy and rigidity of the support sections.
In the suspension frame mounting structure of Patent Literature 1, a portion between the front end of the front side frame and the front fastening section is set as a collision stroke portion when a front collision load is acted from the front of the vehicle. A portion between the front and rear fastening sections is set as a crush preventing portion (portion not to be crushed) to prevent crush when the front collision load is acted.
However, if the front part of the vehicle body of the vehicle is not long enough to secure sufficient collision stroke portion from the front end to the front fastening section of the front side frame, some means have to be provided to absorb the front collision load from the front of the vehicle.
As in the suspension frame mounting structure of Patent Literature 1, the structure for the rear part of the vehicle body that supports the rear sub-frame of Patent Literature 2 also includes the collision stroke portion set between the rear end and the rear fastening section of the rear side frame to absorb impact when the rear collision load is acted from behind the vehicle, and a crush preventing portion (portion not to be crushed) set between the rear fastening section and the front fastening section to prevent crush when the rear collision load is acted. However, if the vehicle cannot secure sufficient collision stroke portion from the rear end to the rear fastening section of the rear side frame, some improvements have to be made to sufficiently absorb the rear collision load from behind the vehicle.
Further, in the structure for the rear part of the vehicle body in which the pair of rear side frames extend in the front-rear direction of a vehicle and the rear sub-frame is supported by the rear side frames, a filler pipe that supplies fuel to a fuel tank is arranged in the collision preventing portion between the rear fastening section and the front fastening section, with the filler pipe being protected in the collision preventing section. If, however, the vehicle cannot secure sufficient collision stroke portion from the rear end to the rear fastening section of the rear side frame, some improvements have to be made to protect the filler pipe.